(a) Field of the Invention
The present invention relates to a photoresist composition, and more particularly to a photoresist composition that can endure heat of a high temperature in a photo process progressing pattern formation during LCD-TFT panel production.
(b) Description of the Related Art
The polymers used in photoresists for LCDs are divided into a nega-type and a posi-type according to solubility characteristics of the exposure part and the non-exposure part. The photoresists embody a resolution of 0.3 μm or more as a result of improved solubility characteristics due to various studies on molecular weight distribution, the meta/para ratio of cresol, conjugation position of methylene groups, ester bonds of photoactive compounds, component ratios, etc.
The performance development of photoresists (PR) used in the photo process progressing pattern formation during LCD-TFT panel production is a very important matter in determining production line output.
Presently, an N+ ion doping process, and a metal and nitride dry etch process of Poly process at a low temperature in a mass production line uses a metal film and a photoresist as a mask.
In the case of an N+ ion doping process, if the metal film used in the mask is substituted for the PR used before the process, the deposition process of the metal film is eliminated, and therefore process simplification and productivity improvement can be obtained.
However, since the photoresist has a heat resistance of about 130° C., if the photoresist is applied in a dry etch process, the PR burns because of the extreme heat and plasma of the process due to the high power of the dry etch equipment, and even after the full ashing process, stripping does not occur properly, and in the case of the metal dry etch damage occurs. In order to solve this problem, the related art uses a hard bake process again after the photo process, and then performs ashing and dry etching.
That is, the positive photoresist currently used does not undergo an ion doping process at a high temperature, and thus there is a concern about flowing. Also, as mentioned, when a nitride dry etch process such as with metal, silicon nitride, and a third layer film (SiNx/a-Si/n+ a-Si) progresses, it does not play an effective role as a mask due to the burning phenomenon of the photoresist. Accordingly, in order to solve the burning phenomenon, the photo process progresses, and then the hard bake process is performed again, but the process is difficult to carry out because of intermittent residue that occurs in the PR pattern image at the glass edge, and process progression is impossible due to the burning phenomenon of the PR even in the multi-metal layer metal dry etch process (Mo/Al—Nd or Mo/Al—Nd/Mo).
Therefore, development of a new photoresist having superior heat resistance, capable of enduring heat of a high temperature (about 160° C.), is needed.